Inductive position-measuring devices are used, for example, as rotary encoders to determine the angular position of two machine parts rotatable relative to each other. In inductive position-measuring devices, excitation coils and receiver coils are often applied, for instance, in the form of printed conductors on a shared printed circuit board that is joined firmly to a stator of a rotary encoder, for example. Situated opposite this printed circuit board is a graduation element, on which electrically conductive and non-conductive surfaces or bars and gaps, alternating at periodic intervals, are applied as graduation structure, and which is joined in rotatably fixed fashion to the rotor of the rotary encoder. When an electric excitation current changing over time is applied to the excitation coils, signals which are a function of the angular position are generated in the receiver coils during the relative rotation between rotor and stator. These signals are then further processed in evaluation electronics.
In addition, inductive position-measuring devices are also used frequently for the direct measurement of longitudinal displacements along an axis. In so doing, the same measuring principle is used as for the rotary encoders indicated above, however, the receiver coils and the graduation structure then extend along the straight-line axis.
Inductive position-measuring devices of this type are often used as measuring devices for electric drives to determine the relative movement or the relative position of corresponding machine parts. In this case, the position values generated are supplied to sequential electronics for controlling the drives via a suitable interface configuration.
European Patent No. 1 750 101 describes an angle-measuring device, in which, in addition to measuring the angular position, an axial displacement is determinable as a function of a measured temperature.